MS – PS1 - 5 Conservation of Mass

CHEMISTRY Unit 1 - Day 11 Do Now: OBJECTIVE(NGSS MS-PS1-5): Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved. Do Now: Element Identification and Word Search Today: Conservation of Mass Balancing Act packet Do Later: SIA articles or Any unfinished notebook pgs

Do Now: Today: Do Later: CHEMISTRY Unit 1 - Day 12 OBJECTIVE(NGSS MS-PS1-5): Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved. Do Now: Finish Balancing Reactions pg 4 Finish Element Word Search (find 20) Today: Review Balancing Reactions LAB: Conservation of Mass Reaction in a Bag - PARTS A & B Do Later: SIA articles or Any unfinished notebook pgs

Do Now: Today: Do Later: CHEMISTRY Unit 1 - Day 13 OBJECTIVE(NGSS MS-PS1-5): Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved. Do Now: Elements and Compounds crossword Today: LAB: Conservation of Mass Reaction in a Bag –PART B & PART C (if time) DVD Chemistry Field Trips Do Later: FINISH LAB QUESTIONS SIA articles or Any unfinished notebook pgs

Do Now: Today: Do Later: CHEMISTRY Unit 1 - Day 14 OBJECTIVE(NGSS MS-PS1-5): Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved. Do Now: Any unfinished notebook pgs ? NOTEBOOK check Turn in Reaction in a Bag Lab Today: SIA Presentations Greatest Chemical Discoveries Do Later: SIA articles or Any unfinished notebook pgs

Do Now: Today: Do Later: CHEMISTRY Unit 1 - Day 15 OBJECTIVE(NGSS MS-PS1-5): Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved. Do Now: Conservation of Mass Review Worksheet Today: Conservation of Mass Review Review Lab and Balancing Equations Finish SIA Presentations Finish Greatest Chemical Discoveries Do Later: Any unfinished notebook pgs

Balancing Act

Chemical Reactions Review… Is the process where physical and chemical properties of the original substance change into a new substance with different physical and chemical properties If there is no new substance there has been no reaction Reactants enter into the reaction Products are produced by the reaction

Chemical Reactions Review… Chemical equations describe chemical reactions using symbols and numbers. 2Na + SrCl2 ® Sr + 2NaCl Coefficients (in red) The large numbers in front of chemical formulas. The number of molecules of the substance in the reaction

Chemical Reactions Review… Chemical equations describe chemical reactions using symbols and numbers. 2Na + SrCl2 ® Sr + 2NaCl Subscripts (in Green) The small numbers to the lower right of chemical symbols Represent the number of atoms of each element is in the molecule

Chemical Reactions Review… Atoms can neither be created nor destroyed during a chemical reaction…Mass MUST remain constant You have to end up with the same number of atoms you started with, but in a different arrangement So balanced equations have the same number of atoms on each side of the YIELDS “®“ sign Law of Conservation of Mass

Balancing Chemical Equations (ALWAYS USE PENCIL) Check for DIATOMIC molecules H2 , N2 , O2 , F2 , Cl2 , Br2 , I2 , and At2 You cannot change the subscripts of these elements in an equation… whenever they are by themselves, these must be written with the subscript 2.

Balancing Chemical Equations Count the number of atoms on each side of the reaction: ___Na + ___MgCl2 ® ___Mg + ___NaCl Sodium=____ ® Sodium=____ Magnesium=____ ® Magnesium =____ Chlorine= ____ ® Chlorine=____ 1 2 1

Balancing Chemical Equations Balance the metals first then the nonmetals ___Na + ___MgCl2 ® ___Mg + ___NaCl Sodium=____ ® Sodium=____ Magnesium=____ ® Magnesium =____ Chlorine=____ ® Chlorine=____ 2 2 1 2 X 2 1 X 2 X 2

Balancing Chemical Equations If they are in your equation, balance OXYGEN then HYDROGEN last Recount all atoms and check your work! Work from the bottom to top until you find any error. If every coefficient will reduce, rewrite in the simplest whole number ratio

Balancing Chemical Equations Lets try an easy one: ___H2 + ___O2 ® ___H2O Hydrogen=____ ® Hydrogen=____ Oxygen=____ ® Oxygen =____ 2 2 2 1 X 4 2 X 4 X 2

Balancing Chemical Equations Lets try one more: ___Na + ___HCl ® ___H2 + ___NaCl Sodium=____ ® Sodium =____ Hydrogen=____ ® Hydrogen=____ Chlorine=____ ® Chlorine =____ 2 2 2 1 X 2 1 2 X 2 X 2 X 2 X 2

Balancing Act ___Mg + ___O2 ® ___MgO ___Ca + ___O2 ® ___CaO ___H2O2 ® ___H2O + ___O2 ___N2 + ___H2 ® ___NH3 ___Cu2O + ___C ® ___Cu+ ___CO2

Reaction in a Bag: PART A THE ORIGINAL REACTION PART B CONTROLLED EXPERIMENTS PART C CONSERVATION OF MASS